/*
  (c) Copyright 2004, 2005, 2006, 2007, 2008 Hewlett-Packard Development Company, LP
  [See end of file]
  $Id: SlotValuator.java,v 1.6 2008/01/02 12:07:57 andy_seaborne Exp $
*/

package com.hp.hpl.jena.graph.query;

/**
 	A SlotValuator evaluates to a specific slot in the index values
 	bindings.
 	@author hedgehog
*/

public class SlotValuator implements Valuator
	{
    /**
     	The index in the index values which this SlotValuator
     	looks up.
    */
    private int index;
	
    /**
     	Initialise this SlotValuator with the index to use for lookup.
    */
	public SlotValuator( int index )
	    { this.index = index; }

	/**
	 	Answer the value of the <code>index</code>th element of the
	 	index values bindings.
	*/
	public Object evalObject( IndexValues iv )
	    { return iv.get( index ); }
	
	/**
	 	Answer the primitive boolean value of the <code>index</code>th
	 	element of the index value bindings, which must be a 
	 	<code>Boolean</code> value.
	*/
	public boolean evalBool( IndexValues iv )
	    { return ((Boolean) evalObject( iv )).booleanValue(); }        
	}

/*
	(c) Copyright 2004, 2005, 2006, 2007, 2008 Hewlett-Packard Development Company, LP
	All rights reserved.
	
	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions
	are met:
	
	1. Redistributions of source code must retain the above copyright
	   notice, this list of conditions and the following disclaimer.
	
	2. Redistributions in binary form must reproduce the above copyright
	   notice, this list of conditions and the following disclaimer in the
	   documentation and/or other materials provided with the distribution.
	
	3. The name of the author may not be used to endorse or promote products
	   derived from this software without specific prior written permission.
	
	THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/